The new school year was supposed to bring a great wave of new academies. In the event, it will be a trickle. In June Michael Gove claimed that 1,100 schools had applied for academy status. Then it turned out the true number was 153. Take away those not yet approved, and it looks like fewer than 50 academies will open this year. Gove's obsession with school freedom is not being driven by demand from headteachers.

So what is driving Gove's reforms? It is ideology all the way. Look first at his changing justifications: back in 2009, he claimed that his inspiration was Sweden, where a system of free schools was giving parents new choices and driving up results for the poorest. Then the evidence came out. Even in that most equal of countries, free schools had benefited only the children of wealthy parents, widening opportunity gaps.

Watching from the US, that still seems a strange star to be chasing. Yes, the best charter schools are thriving: freed from constraints, they're fighting in the ditches – with 10-hour days and Saturday school – to buck trends for disadvantaged kids. But with over 5,000 of the schools now serving 1.5 million children, it's not enough to talk about a handful of successes.

The hard truth is that, the more you look at the US charter school movement, the more the glow fades. Stanford University found that fewer than one in five charter schools were outperforming comparable state schools; about half were performing at a similar level; and 37% were doing "significantly worse".

So yes, Gove can point to successes, but for every one there are two hidden failures. Indeed, of the 5,250 charter schools that have opened here since 1992, one in eight has closed. Last year, nine out of 10 schools in the Texans Can group were rated "academically unacceptable" by the state. On one campus, slated for closure, not a single freshman had gone on to graduate. Yet the Can chief executive still drew a salary of $236,000 (£150,000).

Elsewhere, charter providers have been charged with serious financial mismanagement. Several have been caught excluding huge numbers of students to boost results. Serious concerns are growing over the large, for-profit industry that has sprung up around this lucrative sector. One school offered students $100 to recruit friends, chasing the public money that would come with them.

The point is not that additional freedoms are bad but that, on the basis of evidence, they're a curious obsession. As the US experience shows, schools are not all helium-filled balloons, tethered by government and straining to soar. But nor are they all lead weights, destined to sink without support. Instead, cast adrift, some thrive and some fail; they simply float apart.

Gove may talk of charter schools as a system forging ahead of the pack, but in reality they're a roll of the dice from one that's falling behind. On international tests in reading, science and maths, US students made no gains from 1964 to 2003. On almost all measures the US school system now trails the UK's. Many in a school system paralysed by toxic union relations, perpetual funding crises and fragmented governance have given up on improving from within. Charter school leaders have become vigilantes, going it alone.

That's not an ambitious reform agenda for the UK, any more than it is one based on evidence. In June Gove told school leaders: "Government action has held our education system back" – and that basic disbelief in government – tired old Tory ideology – is driving this destructive experiment.